1. Field of the Invention
The present invention relates to a component package that is formed integrally with a heat exchanger. The present invention more particularly relates to a component package that has a heat exchanger and that is appropriate for use as an electrical component package wherein a liquid-cooled heat exchanger is formed integrally with a cavity-shaped package that forms a concavity in a metal plate for storing the electrical component; i.e., a stiffener or heat spreader.
2. Description of the Related Art
The rate at which computer equipment has been decreasing in size and increasing in performance has accelerated at a greater pace over the past several years. However, the amount of heat generated from semiconductor elements and integrated circuits has also increased along with performance, and efficient methods for cooling this heat are sought for further advances in miniaturization and performance. In order to cool highly integrated, high-output chips and the like, it is common for heat radiators to be attached to the package and forced-air cooling to be performed using cooling fans as necessary.
An electrical component package configured having integrally formed heat-radiating fins is proposed in JP-A 2001-127201. The package disclosed in this document will be described with reference to FIGS. 28A and 28B.
A package 200 is composed of metal and shaped into a cavity that forms a square concavity 202 on a surface 200a. A heat radiator 201, which is composed of a plurality of heat-radiating fins 201a, is formed integrally on the other surface 200b of the package 200. The heat-radiating fins 201a are integrally formed by thinning down the surface of the metal plate that forms the material of the package 200. The heat-radiating fins 201a are shaped as thin, square plates and rise from the surface 200b at a prescribed angle and with lateral symmetry.
A wiring substrate 203, which is composed of a TAB tape, a flexible printed substrate, or a normal printed substrate, is affixed to the surface 200a of the package 200. Printed wiring (not shown) is positioned on the wiring substrate 203 between numerous terminal parts 204 and external terminals provided to the outer edge.
The chips of a semiconductor integrated circuit 205 are housed in the concavity 202. Numerous terminals 206 that are provided to the semiconductor integrated circuit 205 are electrically connected by bonding wires 207 and the terminal parts 204 of the wiring substrate 203. A sealant 208 is injected into the concavity 202 of the package 200, sealing the semiconductor integrated circuit 205 and the bonding wires 207. Solder balls 209 are positioned at the external terminals provided to the outer edge of the wiring substrate 203. The solder balls 209 are melted under heating on prescribed locations on the circuit substrate of an electrical device (not shown), whereby the wiring substrate 203 and the circuit substrate of the electrical device are electrically connected.
The heat radiator 201 is formed integrally on the surface 200b of the package 200, whereby heat from the package 200 can be conveyed directly to the heat radiator 201. The loss of transmitted heat can therefore be reduced and heat radiation efficiency can be improved.
However, the following problems must be resolved in the package 200 of this configuration. First, the heat-radiating surface area of the heat-radiating fins 201a must be large in order to allow radiation of the heat generated from the semiconductor integrated circuit 205 housed in the concavity 202 of the package 200, and the heat-radiating fins 201a must therefore be tall. As a result, the package 200 increases in thickness and may not be able to be mounted on the electrical equipment of small-sized computers and the like.
Additionally, on a small package 200, the height to which the heat-radiating fins 201a can be formed is limited, so that an adequate heating-radiating surface area will be unobtainable. The semiconductor integrated circuit 205 may therefore not be adequately cooled.
Further, since the heat-radiating fins 201a are formed on the package 200, the stability of the package 200 is difficult to maintain when the semiconductor integrated circuit 205 is accommodated in the concavity 202 or when the wiring substrate 203 is affixed. Commonly used automated production lines therefore cannot be employed, and a specialized production line must be provided. Large investments in equipment are therefore necessary.